“The water finally returned. Then we had to fiddle with the computers, trying to get those lights on,” said Norah later, with a laugh. “We even called art technicians in New York. Nothing worked. I’m convinced we have a poltergeist.”

But their 240 guests were convinced they’d enjoyed a grand time at the Stones’ beloved art bash.

In between celebrating the 25th anniversary of their Calistoga property and their 30th wedding anniversary in June, this was the couple’s fifth such “Stonescape” exhibition since the 2007 completion of their private cave, itself an art-worthy commission by Bade Stageberg Cox Architects.

Inside starred “Convergence,” an exhibition curated from the Stones’ collection. Four of the 17 artists were on hand (Antek Walczak, Amalia Ulman, Bill Hayden, Alex Israel) with their works that explore how contemporary artists respond to a world obsessed with spectacle, the cult of celebrity and the pervasiveness of social media.

Snaking among the crowd was a working train — a 1:10 scale model of a Union Pacific locomotive that is actually an artwork, “The Hungry Messenger, 2015,” by Josephine Pryde, whose 2015 show at CCA Wattis Institute of Contemporary Art garnered her a Turner Prize nomination. Joyful guests rode its miniature rails to tour works within the cave.

Outside, verdant grounds were framed by a field of sunflowers, crowned by redwood trees and bracketed by a bodacious pool topped by another Turrell Skyspace that can only be experienced by swimming under the water and up into the structure.

Sipping “Turrell” Tequila cocktails, named in honor of the artist, guests lined up for food-truck fare, which they set on two long planks of reclaimed Sugar Pine that Norah described as “132-people long.” Designed by master woodworker Evan Shivley, the planks were playfully adorned with Japanese anime toys.

“I’ve designed Norah’s tables the last few years, and we always use fresh material,” said Shively, whose Arborica mill is in nearby Marshall. Emphasizing the unsullied essence of the salvaged wood, Shivley added, “There’s something to that old saying, ‘Never been kissed.’”

But there is one work among the Stones’ collection along a curved cave wall that has been kissed quite often: “Untitled 2011 (Police the Police),” a monumental black-and-white mural by Rirkrit Tiravanija.

The artist unveiled, and worked on that piece live, when it debuted four years ago at Stonescape. It depicts drawings culled from news images of political activists and social justice protests. His themes are about inclusivity, so Tiravanija has allowed approved images, such as Black Lives Matter and marriage equality, to be added to the mural by S.F. Art Institute students.

On the floor in front of the mural is a pile of T-shirts emblazoned with the phrase “Police the Police” and “Stonescape,” which, naturally, every guest scooped up.

“The T-shirts are meant to be worn, inspiring further thought after experiencing the art,” said Stone. “It’s really incredible to watch Rirkrit’s work grow and continue to examine crucial social movements in our world.”

Many of the young artists among the Stones’ collection are both appreciative, and impressed, by the couple’s persistent artistic exploration.

“If you look around this exhibition, it’s incredible. But it’s not typical of what you’d find among collectors of the Stones’ generation,” noted artist Alex Israel. “Norah and Norman are so adventurous in their tastes and open to exploring new themes. They are really radical thinkers. It’s amazing.”